Method and system for diagnostics and troubleshooting in
home network deployments
Technical field
The invention relates to the field of diagnostics and
troubleshooting in home network deployments. More in
particular, the invention relates to a method and a system
for analyzing at a remote server a problem of a home
network .
Background
If a failure occurs within the home network, currently, only
manual troubleshooting by service operator technicians or
the customers themselves exists. This type of
troubleshooting is typically a reaction to complaints of the
customer. A complaint triggers the dispatch of technicians
to investigate the problem. Such a procedure is time
consuming and highly costly.
Summary
The object of embodiments of the present invention is to
provide a method and a system allowing a more pro-active
diagnostics and troubleshooting approach for problems
occurring in the home network.
According to an embodiment of the invention, there is
provided a method for analyzing at a remote server, a
problem of a home network. The method comprises the
following steps performed at a remote server which is
connected through the internet with the home network. First,
reference data of at least one home network performance
parameter covering a frequency band, are stored. Those
reference data correspond with a normal behaviour of the
home network, and may e.g. be obtained during a preconf
iguration step. In a next step, measurement data of the
at least one home network performance parameter covering the
frequency band, are obtained through the internet,
preferably using an application layer remote management
protocol. Next, the measurement data are compared with the
reference data to determine qualification data qualifying
the problem.
Using such a method, a problem can be detected and analyzed
remotely, based on measurement data which are also obtained
remotely. Embodiments of such a method can provide a pro
active automatic troubleshooting method, allowing to detect
problems even before a customer complains .
According to a preferred embodiment, the method may be
specifically adapted for use with a series of home
communication devices/technologies. In that way, account can
be taken of the most common home communication
devices/ technologies . For those home communication
devices/technologies one or more relevant frequency bands
are determined, i.e. the frequency bands in which more than
one home communication device may operate. The reference
data and the measurement data are then stored/obtained for a
frequency band which covers those one or more relevant
bands. The determining of qualifying data may comprise
determining an affected frequency band of the measurement
data in which the measurement data differs from the
reference data by at least a predetermined threshold. The
method may further comprise recommending a solution to the
problem based on the qualification data, and may in
particular comprise indicating a device of the series of
home communication devices based on the affected frequency
band, as the device that causes an interference problem.
According to a preferred embodiment, the measurement data
are obtained using an application layer protocol for remote
management, e.g. the TR-069 protocol. TR-181 discloses a
device data model for TR-069, see http :// w .broadbandforum
.org/ technical/download/TR- 181 Issue -2 .pdf . This
document is included herein by reference. See also the data
model definition which can be found on http ://www .broadbandforum
.org/ cwmp/ tr-181-2-4-0. html and which discloses in the
section "device .upa .diagnostics" that it can be indicated to
carry out port management tests in order to obtain network
measurement data of network parameters such as the channel
frequency response (CFR) and the signal-to-noise ratio
(SNR) . This disclosure is also incorporated by reference.
According to a preferred embodiment, the home network is
connected to the internet through a home gateway, and the
network measurements are obtained through the home gateway.
The home gateway is typically a TR-069 enabled device
adapted to obtain the measurement data of the at least one
home network performance parameter. Note however that the
remote server may also communicate directly with a
communication device of the home network instead of with the
home gateway.
The home network performance parameter is typically a
parameter of the physical layer of the home network.
According to a preferred embodiment, the at least one home
network performance parameter comprises at least one of the
following, preferably in the form of a frequency dependent
vector: channel frequency response (CFR), signal-to-noise
ratio (SNR) , bit error rate (BER) , cyclic redundancy check
(CRC) , retransmission counter, a noise level. Depending on
the type of information needed by the service operator, one
or more of said home network performance parameters may be
measured on request of the remote server. According to
exemplary embodiments, the CFR parameter may be used on its
own, or in combination with a noise parameter, such as SNR.
Also, the CFR parameter may be combined with BER and/or CRC
and/or retransmission counter parameters. Alternatively, the
CFR parameter may be combined with a bit-allocation mapping
parameter .
According to a preferred embodiment, the obtaining of
measurement data comprises obtaining a plurality of vectors
for a home network performance parameter. Each vector
comprises values for a series of different frequencies.
According to another aspect of the invention, there is
provided a system adapted for analyzing remotely a problem
of a home network. The system comprises a data storage
storing reference data of at least one home network
performance parameter covering a frequency band, which
reference data corresponds with a normal behaviour of the
home network. The system further comprises at the remote
server, a data collector adapted for requesting and
receiving through the internet, measurement data of the at
least one home network performance parameter covering the
frequency band. Further, there is provided a processor
adapted for comparing the measurement data with the
reference data to determine qualification data qualifying
the problem.
The data collector is preferably adapted to communicate
through a remote management application layer protocol, such
as the TR-069 protocol to request and received the
measurement data.
Further, the system may comprise a recommending means,
adapted to recommend a solution to the problem based on the
qualification data.
According to a preferred embodiment, the system is adapted
for use with home networks which comprise one or more of a
predefined series of home communication devices. For that
predefined series of home communication devices, one or more
relevant frequency bands are determined. Those relevant
frequency bands typically correspond with frequency bands in
which more than one home communication device of the series
of home communication devices operates. In this embodiment,
the date storage stores reference data for a frequency band
covering at least the one or more relevant bands, and the
data collector is adapted to request and receive measurement
data covering at least the one or more relevant bands . The
processor is then preferably adapted to determine qualifying
data by determining an affected frequency band of the
measurement data in which the measurement data differ from
the reference data by at least a predetermined threshold.
The recommending means may be adapted to recommend a
solution by indicating a device of the series of home
communication devices based on the affected frequency band,
as the device that causes an interference problem.
The system may comprise a TR-06 9 enabled home gateway
adapted to receive a request for the measurement data of the
at least one home network performance parameter, to obtain
the measurement data, and to send the measurement data to
the data collector through the internet. According to
possible embodiments, the system may further comprise a
plurality of home networks using any one of the following
technologies: G.hn, HomePlug, UPA, HomeGrid. The home
network may comprise e.g. coax lines and/or phone lines
and/or power lines. A typical example of a home
communication device is power line adaptor.
The data collector is preferably a TR-069 enabled device.
Such a device will allow collecting measurement data of the
home networks through the internet by sending a suitable TR-
069 request message. Preferably, the data collector is
adapted to collect at least one of the following, preferably
in the form of a frequency dependent vector: channel
frequency response (CFR) , signal-to-noise ration (SNR) , bit
error rate (BER) , cyclic redundancy check (CRC) ,
retransmission counter, a noise level.
Brief description of the figures
The accompanying drawings are used to illustrate presently
preferred non limiting exemplary embodiments of methods,
servers and systems of the present invention. The above and
other advantages of the features and objects of the
invention will become more apparent and the invention will
be better understood from the following detailed description
when read in conjunction with the accompanying drawings, in
which :
Figure 1 illustrates schematically a first embodiment of a
system of the invention;
Figure 2 is a flow chart illustrating an embodiment of the
method of the invention;
Figures 3A and 3B illustrate respectively the connected CFR
and power line noise for the embodiment of figure 1 ;
Figure 4 illustrates schematically a second embodiment of a
system of the invention;
Figures 5A and 5B illustrate schematically an example a CFR
with and without interference; and
Figures 6A and 6B illustrate schematically a graph showing
the number of bits allocated per subcarrier for a normal bit
loading process (without interference) and for an effective
bit loading process (with interference) , respectively.
Detailed description
A first embodiment of the system of the invention is
illustrated in figure 1 . The network architecture comprises
a remote server 1 which is connected through the internet 6
and through an access node 2 with a home network 3 . In the
home network 3 , different frequency bands may be used for
different technologies used in the home network. Currently,
different standards are available to enable broadband data
communication required by in-house high data rate
applications over power line cables. The most relevant
technologies today are HomePlug and International
Telecommunication Union (ITU), G.hn standards, but there are
still some products based on former UPA association (now
HomeGrid) . Due to different standardisations and
specifications those technologies utilise different
frequency bands. Consequently, a problem may arise when
adaptors based on different technologies are working within
the same network or in nearby areas in their respective
frequency bands. Interference in overlapping bands may cause
significant problems and should preferably be detected
remotely and dealt with timely.
Now embodiments of the invention will be illustrated
referring to specific examples of technologies used in the
home network, but the skilled person will understand that
the invention is also applicable for other existing or
future technologies operating in similar or different
frequency ranges. In the G.hn standard, 50 MHz and 100 MHz
bands are available for coax, phone and power lines. In the
HomePlug specification, depending on the standard generation
(e.g. HomePlug 1 or HomePlug AV or HomePlug AV2 , etc.)
different frequency bands, such as 30 MHz and 100 MHz bands
are also utilized by HomePlug technology. For UPA devices a
band of 30 MHz may be used for power line communication. In
view of those frequency ranges, it is understood that
interference may arise if adaptors operate nearby each
other.
A basic idea of embodiments of the invention is to propose a
method and system for home network multiple technology
detection and troubleshooting of interfering devices and/or
for identifying possible disturbers of a home network. In
particular, embodiments of the invention are valuable for
diagnostics and troubleshooting of interference problems
related to G .hn/HomePlug/UPA/HomeGrid home networking
deployments .
In the exemplary embodiments illustrated below, a power line
communication home network deployment is considered, but the
skilled person understands that the invention is equally
applicable when using other communication lines, such as
coax and phone lines.
In the embodiment of figure 1 , the remote server 1 is first
used to initiate the measurement of different home network
performance parameters over a residential gateway 4 , see
arrow 5 . The residential gateway 4 communicates with the
home network devices and provides the network performance
parameter data to the remote server 1 upon request . The
obtained measurement data for the home network performance
parameters are used to estimate alien interference. In the
example of power line adaptors, e.g. the following network
performance parameters of the physical layer of the home
network may be obtained:
- a channel frequency response (CFR) in the form of an
average attenuation or in the form of a frequency- dependent
vector ;
- signal-to-noise ratio (SNR) in the form of an average
attenuation or frequency- dependent vector;
- bit error rate (BER) or other CRC or retransmission
counters, in the form of a table;
- noise level in the form of an average attenuation or
frequency- dependent vector;
- bit-allocation mapping, in the form of a table.
Figures 3A and 3B illustrate respectively an example where a
CFR vector and a power line noise vector is obtained from a
power line adaptor in the home network.
Now it will be assumed that the home network contains a
plurality of power line adaptors, wherein one adaptor of the
power line adaptors is operating based on the HomePlug
specification, while the other power line adaptors are
operating based on a G.hn standard specification. In this
example, the different power line adaptors may be included
in the same home network 3 , as illustrated in figure 1 , or
may be included in different neighbouring home networks 3 as
illustrated in figure 4 . In the example of figure 4 , e.g.
Net C may comprise a HomePlug adaptor, whilst Nets A and B
may comprise a G.hn adaptor. Note that in the example of
figure 1 , where it is assumed that different adaptors are
located within the same power line network (Net C ) , the
problems may be more severe.
Now an embodiment of the method of the invention will be
illustrated referring to figure 2 . In a first stage 21,
measurement data of at least one home network performance
parameter are collected from the network devices by using an
application layer protocol for remote management, such as
the TR-069 protocol. Examples of home network performance
parameters that may be collected are listed above. In the
present example, we will first consider that the CFR
parameter as frequency- dependent vector was measured and
collected by the remote server.
In the second stage 22, the alien interference is estimated
based on the collected measurement data. In the example
where the CFR parameter was measured, the frequencydependent
CFR vector may be segmented in order to focus on
the relevant frequency bands, i.e. on the overlapping areas
of the frequency bands of different technologies. E.g., the
30 MHz band is used both in HomePlug and G.hn devices, so
that interference may arise in this band. This is
illustrated in figures 5A and 5B which show respectively the
CFR parameter with and without interference for the 100 MHz
frequency band. Figure 5B shows that the interference occurs
in the 30 MHz frequency band. In the example of figures 5A
and 5B the impact of noise is not taken into the
consideration for the sake of simplicity. However, the
skilled person will understand that noise may be taken into
consideration .
Now an example will be described of an algorithm that may be
used to determine qualification data qualifying the
interference problem using the measured CFR data. The
algorithm is based on a comparison of the measured CFR with
a reference CFR stored in a database. For each frequency an
average power level of the measured CFR may be calculated
and compared with a reference power level. This is repeated
for each frequency to detect an affected frequency band AB .
According to a possible implementation, the standard
deviation between the measured signal and the reference
signal may be calculated for each frequency. If the entire
available band is affected more than a predefined threshold,
it is determined that the interference is not only due to an
alien power line system, and the method proceeds to stage
23 . If a part of the entire available band is having a
relatively high standard deviation, it is determined that
interference is detected, and the method goes to stage 23 .
In the example above, the interference estimation of stage
22 was done based on the CFR vector. Now another example
will be given where the interference estimation is based on
a measured bit-allocation mapping parameter. Each technology
used in the home network is using a bit-allocation algorithm
which allocates the bits to each subcarrier used in the
system. Bit-allocation tables are held in the memory of the
system and used for re- synchronization if necessary. By
collecting measurement data of the bit-allocation mapping
parameter in the home network, interference may be detected
as follows. For each subcarrier in the relevant frequency
band, the modulation level of the "new" measured bitallocation
table is compared with an "old" reference bitallocation
table. This is illustrated in figures 6A and 6B .
If the new measured level for a particular subcarrier is
affected by more than a predefined threshold compared to the
old reference level of the bit-allocation table, than it is
determined that that subcarrier is affected. If the entire
available band is affected more than the threshold, it is
determined that the interference is not only from the alien
technology, and the method proceeds to stage 23 . If it is
determined that a part of the frequency band is affected by
more than a predefined threshold, interference is detected
and the method proceeds to stage 23.
In the paragraphs above, two examples have been illustrated
using the CFR vector or the bit-allocation mapping. In
practice, typically, the interference estimation may be
based on the following parameter or combinations of
parameters :
- the channel frequency response (CFR) on its own;
- CFR in combination with SNR, and optionally in combination
with bit-allocation mapping or BER or another CRC or
retransmission counter;
- CFR in combination with bit-allocation mapping or BER or
CRC or retransmission counter.
In stage 23, a recommendation is given to the service
operator. This recommendation may be given upon request of a
service operator in view of a complaint of a customer, but
may also be given in the form of a potential alarm before
the customer complains. The method of the invention may be
performed continuously at a remote server for all home
networks corresponding to a particular service operator, and
the service operator may be updated continuously of any
interference problems that are detected. The recommendations
may then be used by the service operators for identifying
alien devices or for determining how to reconfigure a
device, and in particular for changing the frequency band to
an unaffected location.
The reference data are stored in a database which is
accessible by the remote server. The reference data may be
stored definitively stored during a pre-conf iguration step,
wherein a home network is measured whilst performing
normally. According to an alternative embodiment, the
reference data may be continuously updated by performing
home network performance parameter measurements on all the
network devices connected to the operator network.
Since most home network communication devices are TR-069
enabled devices, embodiments of the invention will typically
not require any hardware modification at the end user's home
network devices. Embodiments of the server of the invention
may be implemented within the service operator's management
centre and can be used as part of more sophisticated
monitoring tools.
Whilst the principles of the invention have been set out
above in connection with specific embodiments, it is to be
understood that this description is merely made by way of
example and not as a limitation of the scope of protection
which is determined by the appended claims.
1

Claims
1 . Method for analysing at a remote server a problem of a
home network, comprising the following steps performed at
the remote server which is connected through the internet
with the home network:
- storing reference data of at least one home network
performance parameter covering a frequency band, said
reference data corresponding with a normal behaviour of the
home network;
- obtaining, through the internet, measurement data of said
at least one home network performance parameter covering
said frequency band;
- comparing said measurement data with said reference data
to determine qualification data qualifying the problem.
2 . Method of claim 1 , further comprising recommending a
solution to the problem based on the qualification data.
3 . Method of claim 2 , wherein a plurality of home
communication devices operating in a plurality of frequency
bands is defined, said plurality of frequency bands
comprising one or more overlapping bands; wherein said
reference data and said measurement data is obtained for a
frequency band covering at least said one or more
overlapping bands;
wherein determining qualification data comprises determining
an affected frequency band of said measurement data in which
said measurement data differs from said reference data by at
least a predetermined threshold; and
wherein recommending a solution comprises indicating a
device of said plurality of home communication devices based
2
on the affected frequency band, as the device that causes an
interference problem.
4 . Method of any of the previous claims, wherein obtaining
measurement data comprises using an application layer
protocol for remote management to request and receive said
measurement data.
5 . Method of claim 4 , wherein said application layer
protocol for remote management is the TR-069 protocol.
6 . Method of any of the previous claims, wherein said at
least one home network performance parameter comprises at
least one of the following, preferably in the form of a
frequency dependent vector: channel frequency response
(CFR) , signal-to-noise ratio (SNR) , bit error rate (BER) ,
cyclic redundancy check (CRC) , retransmission counter, a
noise level.
7 . Method of any of the previous claims wherein said
reference data is obtained by measuring said at least one
home network performance parameter covering said frequency
band before a problem occurs.
8 . Method of any of the previous claims, wherein said home
network is connected to the internet through a home gateway,
and said network measurements are obtained through said home
gateway .
9 . System adapted for analysing remotely a problem of a home
network, comprising:
- data storage storing reference data of at least one home
network performance parameter covering a frequency band,
3
said reference data corresponding with a normal behaviour of
the home network;
- a data collector adapted for requesting and receiving
through the internet measurement data of said at least one
home network performance parameter covering said frequency
band;
- a processor adapted for comparing said measurement data
with said reference data to determine qualification data
qualifying the problem.
10. System of claim 9 , wherein said data collector is a TR-
069 enabled device adapted to use an application layer
protocol for remote management to request and receive the
measurement data from a home gateway or a device in the home
network.
11. System of claim 9 or 10, further comprising a
recommender adapted to recommend a solution to the problem
based on the qualification data.
12. System of claim 11, wherein a plurality of home
communication devices operating in a plurality of frequency
bands is defined, said plurality of frequency bands
comprising overlapping bands; wherein said data storage
stores reference data for a frequency band covering at least
said overlapping bands; and said data collector is adapted
to request and receive measurement data covering at least
said overlapping bands;
wherein said processor is adapted to determine qualifying
data by determining an affected frequency band of said
measurement data in which said measurement data differ from
said reference data by at least a predetermined threshold;
and
4
wherein said recommender is adapted to recommend a solution
by indicating a device of said plurality of home
communication devices based on the affected frequency band,
as the device that causes an interference problem.
13. System of any of the claims 9-12, wherein said at least
one home network performance parameter comprises at least
one of the following, preferably in the form of a frequency
dependent vector: channel frequency response (CFR) , signalto-
noise ratio (SNR) , bit error rate (BER) , cyclic
redundancy check (CRC) , retransmission counter, a noise
level .
14. System of any of the claims 9-13, further comprising a
home gateway, said data collector being connected through
the internet and the home gateway to the home network,
wherein said home gateway is a TR-069 enabled device adapted
to receive a request for said measurement data of at least
one home network performance parameter, to obtain
measurement data of said at least one home network
performance parameter, and to send said network measurement
data to the data collector through the internet.
15. System of any of the claims 9-14, further comprising a
plurality of home networks using any one of the following
technologies: G.hn, HomePlug, UPA, HomeGrid, said home
network preferably comprising any one or more of the
following: coax line, phone line, power line.